Proposals to initiate text-based discussions on an intellectual property (IP) waiver, rather than more general talks, gained traction at an informal meeting of the World Trade Organization's Agreement on Trade-Related Aspects of IP Rights (TRIPS) council, the official said.

The United States, China, Ukraine and New Zealand have thrown their weight behind the bid to waive certain TRIPS provisions relating to the medical prevention, containment or treatment tools needed to battle COVID-19, said the official.

However, some members "continued to express doubts about the convenience of starting negotiations and asked for more time" to analyze the proposal, the official said.

They included the EU, Australia, Brazil, Britain, Japan, Norway, Singapore, South Korea, Switzerland and Taiwan.

Agreements at the WTO require the consensus backing of all 164 member states.

India and South Africa came forward with the original idea in October. They have submitted a revised proposal, which currently has the express support of 63 WTO members.

The new text which they and other backers have circulated says the waiver should apply not only to vaccines, but to treatments, diagnostics, medical devices and protective equipment, along with the material and components needed to produce them.

It also says the waiver should last for "at least three years" from the date it takes effect, following which the WTO's General Council should determine whether it should be prolonged.

The trade official said differences continued on the question of whether, and to what extent, IP protection was holding up the goal of beating the pandemic, and about the use and potential improvement of existing flexibilities within the TRIPS terms.

Questions were also raised on the duration and termination of the proposed waiver, the official said.

The US said it was open to text-based talks on any proposal that could address the immediate need for increased vaccine production and distribution, the official said.

China said that as the initial proposal had been laid down in October, it was time to move to the next stage, the official added.

Pakistan, Argentina, Bangladesh, Egypt, Indonesia and Kenya were among the countries that expressed the need to start negotiations, said the official.

Meanwhile the EU said the immediate goal should be ramping up production alongside measures such as lifting export restrictions for vaccine ingredients.

Switzerland, also home to major pharmaceutical firms, said WTO members should explore ways to use the flexibilities within TRIPS rather than waiving them altogether, the trade official said.

The TRIPS Council will hold a formal meeting on June 8-9.

More than 1.9 billion doses of COVID-19 vaccines have been injected in at least 213 territories around the world, according to an AFP count.

Just 0.3 percent have been administered in the 29 lowest-income countries, home to nine percent of the world's population.

Proponents argue the temporary removal of IP rights will boost production in developing countries and address the dramatic inequity in access.

That notion has long met with fierce opposition from pharmaceutical giants and their host countries, which insisted patents were not the main roadblocks to scaling up production and warned the move could hamper innovation.

The positions appeared to shift earlier this month, when Washington came out in support of a global patent waiver for vaccines, with other long-time opponents voicing openness to discuss the matter.